To ensure adequate air flow and return to the interior spaces, especially in commercial buildings installed with HVAC systems, it is customary to employ certain techniques to measure the air flow being produced by the system. The procedures used to measure air flow for this purpose have been cumbersome and not amenable to easy manipulation of the measurement devices, which often do not properly fit over the vent opening to provide a tight enough seal to prevent leakage of the airflow, which can lead to inaccurate flow measurements. Vent grilles used in building construction are often of standard 2′×2′ size, however they are sometimes modified to be non-standard for a variety of functional or esthetic reasons during construction and finishing of interior spaces. Sometimes they are crudely retrofitted with wedges, etc., to fit over vent openings that are not of the same size, and these additions create problems when measurement of air flow from the vent is to be measured. In addition, it is often difficult to manipulate the coverage of the grille opening because there is no means of securely fastening the measurement device, e.g. a hood skirt of a flowhood measurement device, to the grille opening. As a result, more than one operator is usually required to both hold the opening of the hood skirt over the vent opening and to record the series of air flow measurements required to diagnose the operating condition of the system and then to adjust the flow of air. Because of the need for more than one worker, the process is time-consuming and costlier because of the amount of manpower needed.
The prior art has not recognized a solution to the need for adapting the opening of an airflow measurement device such as a flowhood, to the standard and non-standard sized openings of ductwork vent grilles, which is easy to manipulate by a single operator and which provides an adequate sealing means to prevent diversion of air flow outside the receptacle of the measurement device, especially if the frame of the flowhood opening and the grille opening are not of compatible sizes. In addition, the devices used in air flow measurement have not been designed to provide a self-sustaining connection between the vent grille opening and the adaptably sized opening of an air flow measurement apparatus, such as the funnel or hood skirt of a flowhood. As a result, the funnel opening commonly has to be held in place by an operator. This adds to the cumbersome nature of the overall process. These deficiencies are satisfied by the design and functionality of the present invention.
In addition, the conventional flowhood frame made to fit hood skirts over vent grille openings is typically equipped with a gasket that is fixed or sealed in place and is not removable. Therefore, when the gasket becomes loose or damage, it cannot be replaced. Consequently, the entire apparatus must be discarded. The present invention address this deficiency in the prior art.
U.S. Pat. No. 6,435,963 discloses a barrier device for preventing staining of the ceiling around a ceiling air delivery structure caused by moisture and dirt deposited from the vent air flow. The barrier device is used with a diffuser and includes a partition and other facets designed to deflect the normal course of airflow from the vent. No means is provided for facilitating optimal measurement of air flow or for connection to an air flow measurement device. U.S. Pat. No. 6,835,129 discloses a boot seal used to temporarily close off air duct openings during construction. The boot seal is fitted directly over the ceiling opening and beneath the structure used to cover the opening. It covers the entire opening while installed so no air flow can be facilitated. U.S. Pat. No. 5,338,255 discloses a mounting shoulder for securing an air duct register to an air duct fitting that is passed through the plaster wall board of a wall or ceiling, particularly where there is no other backing means to which the register can be secured to hold it firmly in place. The mounting shoulder has an attachment strip that is spot welded to the lower edge of an air duct fitting, and a floor plate that is further attached along one edge of the attachment strip to stabilize the installation of the register as screws are manually installed or drilled through. U.S. Pat. No. 6,533,656 discloses a duct vent closure that covers a vent opening which has a hinged closure means that is forced open by increased air pressure and closed by decreased air pressure. This automatic duct vent closure regulates against backflow of treated air originally introduced into a room.
Based on the foregoing, it can be seen that the level of ordinary skill in the field of HVAC maintenance contends with methods of air flow measurement that present a technological as well as a manpower challenge. Not only is the equipment that has long been used and is still being used to facilitate air flow measurement within a building's circulation not amenable to easy attachment of a flowhood air measurement device to vent grille openings in the ductwork, the known process requires multiple personnel to cover the grille opening with a measurement receptacle such as a funnel, to hold the funnel in place, and to adjust it by making crude stencils of cardboard to fit the skirt opening to the size of the grille opening and the frame. There is therefore a need for an apparatus that allows easy and secure connection of a vent grille opening to the receptacle of an air flow measurement device, which is compatible with adjustment means that can be easily sized to fit precisely to the size of various vent grille openings, and which can be operated by a single operator.
The present invention solves these deficiencies and meets the need recognized within the field of the invention by providing an apparatus for securely attaching the opening of a flowhood measurement device to a vent grille opening, adjusting the size of the opening of the flowhood measurement device to match the size of the grille opening to reduce the leakage of air, and providing a seal around the grille opening, thus improving the ease of securing the flowhood measurement device to the grille opening, as well as improving the ease of taking accurate airflow measurements. The present invention further provides a solution to the costly and time-consuming process requiring multiple personnel to measure and adjust the airflow into a flowhood opening.